Known methods and arrangements for working of axially symmetric products from glass by a laser beam are disclosed in DDR patent specification No. 112, 941, U.S. Pat. Nos. 3,770,936 and 3,701,880 and in the Czechoslovak certificate of authorship No. 213,081. All these cited methods are based on the principle of a sufficient absorption of glass of a certain wave length of a laser beam.
A drawback of abovementioned known methods and arrangements is that the laser heat does not pass through the glass mass, but is absorbed within the thin glass surface layer and the required decor is created on the glass surface by evaporation of a local thin glass layer with an accompanying creation of microcracks. A further drawback of the abovementioned known methods and arrangements is the requirement that the laser heat act on the axially-symmetric product from the external side, the resulting necessity of a central clamping and rotation of the axially-symmetric product around the axis of symmetry and a practically rather demanding manipulation of the product.
It is an object of this invention to substantially eliminate the above mentioned drawbacks of creation of a decor on hollow axially-symmetric products by a laser beam.